Niklas Luhmann mug
Niklas Luhmann's personal zettelkasten and academic research surrounding it have definitely popularized the idea of what a slip box is and how it can be useful. However there are too many articles and pieces out there that glorify the idea and seem to credit him with the invention either directly or indirectly. In fact, the idea goes back at least to Conrad Gessner (1516-1565), a Swiss physician and bibliographer. Now you can buy this awesome bumper sticker to remind your favorite index card aficionado or slip-o-phile that we've been taking notes for more than a generation or two.
$15.95